Magneto wrote:
You said "Earth is their only option". That says that they lack the ability to survive anywhere that is not already a habitable planet. Whereas if we were inclined to, we could thrive on a world that is lacks breathable air fairly easily, just use domes, and could survive on worlds that are basically vacuum. In fact, we don't even need the world.
You're scenario also has them being the last of their species. In which case, they're in no position to be making demands, they have no alternative option. Anyway, I think it's fair that we get something in return - their ship, say, and all data they possess...
Which, given that the conditions you've given imply that they've been limping through space in an orion pulse drive ship and hibernating, won't be much; only the cartography data and hibernation tech will be useful. If they're using a generation ship, they already know how to build space colonies, and don't need Terra. If they have relativistic travel, they have access to sufficient energy to terraform planets for themselves. If they can go FTL... well, they have something of value for us, and I'm sure we can come to an arrangement to fix up a neighbouring system for them.
Our scientists would encourage them to share of course! It wouldn't be one way.